Process for the production of trialkyl benzene



- Patented Aug. 5, i947 PROCESS FOR THEPRODUCTION F TRIALKYL BENZENE Vladimir N. Ipatiefi and Carl B. Linn. Riverside,

Ill., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application June 29, 1944, Serial No. 542.805

15 Claims. (Cl. 260-668) This invention relates to an improved process for producing tri-alkyl benzene hydrocarbons from aliphatic ketones, More specifically, our invention is concerned with a method for manufacturing mesitylene from acetone.

An object of this invention is a process for condensing an alkyl ketone to form a substantial yield of poly-alkyl benzene hydrocarbons.

Another object of this invention is to provide an improved process for producing mesitylene from acetone.

One specific embodiment of this invention relates to a proces which comprises treating an alkyl ketone at a temperature of from about 200 to about 450 C. in the presence of a heteropoiy acid catalyst.

.A further embodiment of this invention is concerned with a process for producing mesitylene which comprises treating acetone at a temperature of from about 200 to about 450 C. in the presence of a heteropoly acid catalyst in which one of the components is an element selected from the members of the left-hand columns of groups V and VI of the periodic table.

' Alkyl ketones utilizable in our process for producing poly-alkyl benzene hydrocarbons comprise particularly the methyl ketones including acetone, methyl ethyl ketone, methyl propyl and methyl isopropyl ketones. etc. Aliphatic methyl ketones, when treated by our process, yield symmetrical tri-alkyl benzene hydrocarbons, the simplest of which is mesitylene which is also known as 1,3,5- trimethylbenzene. Aliphatic ketones other than the methyl ketones may also be treated by our process to form hexa-alkyl benzene hydrocarbons. Methyl aryl ketones are also convertible into triaryl benzene hydrocarbons while other alkyl aryl ketones yield tri-alkyl tri-aryl benzene hydrocarbons.

The term heteropolyacid used in this specification and in the claims should be regarded as having the same scope as indicated in the following material quoted from Inorganic Chemistry, by Ephraim, English edition, Gurney and Jackson (1934), p. 434.

The term polyacid is applied to acids which contain several acidic radicals, such as pyrosulfuric acid, (O(SOa)2)H2; pyrophosphoric acid (O(PO3)2)H4; tetrachromic acid (0(CrOa)4)H2; and metatungstic acid, HzWsOrs. When polyacids contain only one kind of acidic radical they are termed isopolyacids, but if one of the radicals is derived from another negative element, the term heteropolyacid is applied. The radicals of vanadic, tungstic, and molybdic acids unite with radicals of other fairly strong acids or with amphoteric metallic hydroxides, to form heteropolyacids. Examples of these are phosphotungstic, phosphomolybdic, and phosphovanadic acids, silico-tungstie or -molybdic acids, and borotungstic acid. It is distinctive of heteropolyaclds that a single radical of one of the acids is united with many, perhaps twelve. radicals derived from the second acid.

Also, the heteropolyaclds which are used as catalysts for the process of our invention are regarded as compounds of the co-ordination type involving acid radicals such as phosphates, arsenates, borates, and silicates surrounded by molecular groupings composed of oxides of molybdenum, tungsten, or vanadium. While the structures of heteropolyaclds are not known with certainty, recent investigators have concluded that phosphotungstie acid has a structure which may be represented as Hs[P(WaO1o)4lxHzO or Certain investigators have expressed the view that the water of crystallization of phosphotungstic acid is packed into interstices between the anions [P(W30io) 4'1". This structure has been considered present also in silicotungstic acid, borotungstic acid, and metatungstic acid which become HiESlWizO-zo], H5[BW12040], and

respectively; whereas other workers indicate that the same type of structure is present in phosphomolybdic acid, H.3[PM012O4o]; arsenomolybdic acid, H3IASM012O40]; and silicomolybdic acid, HdSiMomOal, respectively, and their salts. Also it has been considered probable that all compounds formerly regarded as Hs[X(M02O7) a] should be written H4[XM012O40], where X represents cerium, zirconium, tin, and thorium. Many other complex substances as those containing vanadium and other elements may be of this type. The central tetrahedral group X04 is an essential feature of all the foregoing acids and salts. In heteropolyaclds it is general that a single radical of one of the acids is combined with many radicals derived from the second acid.

The catalysts which we prefer to use in the process of this invention are the heteropolyaclds as defined above and in which one component of the heteropolyacid is an'element selected from the members of the left-hand columns of groups V and VI of the periodic table.

Although heteropolyacids may be used as such in our process, we prefer to so employ solid gran- 3 ular catalytic material formed by impregnating a carrier or supporting material with an aqueous solution of the heteropolyacid and thereafter calcining the impregnated material to form a granular solid utllizable as a reactor iilling material and from which the catalytically active substance 'is not removed readily by water.

The process of our invention is carried out using either batch or continuous types of treatment. In batch type treatment, a ketone or a ketone mixture and a heteropolyacid catalyst of the type herein described are charged to an autoclave and brought to a desired superatmospheric pressure, for example by the introduction of nitrogen to the autoclave. The charged autoclave is then rotated and heated at a temperature of from about 200 to about 450 C. This treatment is continued for a time sumcient that a substantial proportion of the charged ketone is converted into the desired poly-alkyl benzene hydrocarbon such as mesitylene.

Itis preferable, however, to carry out the process in a continuous manner by passing a ketone or mixture of ketones through a reactor containing a calcined granular composite of a heteropolyacid and a carrier maintained at a temperature of from about 200 to about 450 C. and at a superatmospheric pressure generally not greater than about 100 atmospheres. The reaction products obtained from either the batch or continuous types of treatment are separated into unconverted ketone, unsaturated by-products such as mesityl oxide and isophorone and the desired poly-alkyl benzene hydrocarbon, of which mesitylene is representative. Unconverted acetone and by-products, the latter including mesityl oxide and isophorone, are recycled to the process for producing higher yields of polyalkyl benzene hydrocarbons.

Sometimes it may also be desirable to carry out the process in a continuous manner by pumping an aliphatic ketone and an aqueous solution of a water-soluble heteropolyacid through a reactor maintained at the desired temperature but at a pressure suflicient to maintain the reaction mixture in substantially liquid phase and thus avoid separation of solid heteropolyacid from the aqueous catalyst solution. The reaction mixture obtained from such a process is then separated into an organic liquid layer and an aqueous catalyst layer, the latter being generally recycled to the process. The organic liquid layer is then separated by suitable means into unconverted ketone, by-products, and the desired poly-alkyl benzene hydrocarbon. The unconverted ketone and the by-products, the latter including for example mesityl oxide and isophorone, are recycled to the process.

The following examples are given to show results obtained in treating an alkyl ketone in the presence of a heteropoiyacid catalyst at conditions adequate to convert a substantial proportion' of said ketone into a tri-alkyl benzene hydrocarbon.

Example I A phosphotungstic acid-alumina catalyst was prepared by dissolving 8 grams of phosphotungstic acid, 20WO3'2H3PO4-25H2O, in 46 grams. of water and adding thereto 78 grams of 6-14 mesh activated alumina. The alumina so impregnated with the phosphotungstic acid solution was dried at 100 C. for 15 hours and then calcined at 370-425 C. for 1 hour.

42 grams of the catalyst prepared as described above was placed in a steel catalyst tube of 14 mm. diameter and heated at 350' C. while acetone was passed therethrough at a pressure of atmospheres and at an hourly liquid space velocity oi 1 during a period of 20 hours; A total oi 975 grams or acetone thus yielded 4 grams or non-condenslbie gas, 82 grams of condenslbie as, and 845 grams of liquid product. The recovered liquid product was found to contain 470 grams of unconverted acetone, 139 grams of water, 22 grams of mesityl oxide boiling between and 0., 18 grams of a fraction boiling from 135' to C., 132 grams of a mesitylene fraction boiling from 155 to C., 5 grams of material boiling from 170 to 200 C., 17 grams of isophorone boiling from 206 to 220 C., and 31 grams of higher boiling material. The condenslbie gas was found to contain 7.3 mole percent carbon dioxide, 3.5% ethylene and propylene, 0.4% ethane and propane, 58.4% isobutylone, 3.7% n-butylene, 3% butane, 0.5% of pentane and pentenes, and 22.9% of higher boiling material consisting essentially of unconverted acetone.

Thus, 50.8% of the acetone charged underwent reaction. The yields based upon the weight percent of acetone reacting were as follows: mesitylene, 27%; mesityl oxide, 4%; isophorone, 3%; and liquid products boiling above 220 C.,

Example 11 The catalyst employed in this run was similar to that described in Example I, but in addition it was calcined for 2 hours at 650' C. 7

Following the procedure employed in Example I, a total of 1025 grams of acetone was passed during 20 hours through a reactor containing 40 grams of the above described catalyst maintained at 350 C. and at a pressure of 70 atomospheres. The resultant reaction products contained 4 grams of non-condensible gas, 124 grams of condensible gas and 870 grams of liquid product. This liquid product was found to contain 477 grams of unconverted acetone, 139 grams of water, 26 grams of mesityl oxide, 9 grams of liquid boiling from 135 to 155 C., 156 grams of a mesitylene fraction, '5 grams of material boiling from 170 to 206 C., 15 grams of isophorone, and 40 grams of liquid material boiling above 220 C. Analysis of the condensible gas gave the following results: 17:4 mole carbon dioxide; 2.9% ethylene and propylene; 50.5% isobutylene; 3.2% n-butylene; 0.6% of a mixture of ethane, propane and butane; 6.6% pentanes and pentenes, and 18.8% of higher boiling material consisting mainly of unconverted acetone.

In this run, 53.4% of the acetone charged underwent reaction. The yields of products based upon the weight of acetone reacting were as follows:

mesitylene, 28%; mesityl oxide, 5%; isophorone,

3%; and liquid products boiling above 220 C.,

Example III The catalyst employed in this run was prepared by impregnating 96 grams of 6-14 mesh activated alumina with a solution formed by dissolving 10 gram of silico-tungstic acid,

in 60 grams of water. The impregnated material was dried overnight at 100 C. and then calcined at 650 C. for 2 hours.

Following the procedure used in Examples I and II, a total of 935 grams of acetone was passed over 43 grams of the catalyst at 350 C. and at a pressure-oi 70 atmosphere during a period of 20 hours. The resultant reaction product contained 6 grams of non-condensible gas. 85 grams oi. condensible gas, and 821 grams or liquid product. The liquid product was round to contain 429 grams of acetone. 137 grams oi water, 20 grams of mesityl oxide, 8 grams of liquid product boiling i'rom 135 to 155 C., 154 grams of a mesitylene fraction. 8 grams of liquid boiling from 170 to 206 C., 21 grams of isophorone, and 42 grams of liquid material boiling above 220 C.

The condensible gas contained 13 mole of carbon dioxide, 2.4% ethylene and propylene, 0.8% of ethane and propane, 48.5% isobutylene, 4.4% n-butylene, 1.7% of butane, 0.7% of pentanes and pentenes, and 28.5% of higher boiling material consisting essentially of unconverted acetone.

Of the acetone charged, 54.2% reacted. Upon the basis of the acetone reacting, the weight yields of the diilferent products were as follows: 30% mesitylene; 4% mesityl oxide; 4% isophorone; and 8% of liquid boiling above 220 C. The yield of mesitylene obtained was 44% of the theoretical based upon the reaction of 3 molecular proportions of acetone yielding 1 molecular proportion of mesitylene and 3 molecular proportions of water.

Example 11" The catalyst employed in this run was prepared by impregnating 95 grams oi. 6-14 mesh activated alumina with a solution formed by dissolving grams of phosphomolybdic acid, MoOa-2H3P04=48HzO, in 60 grams of water. The impregnated material was dried at 100 C. for 12 hours and then calcined at 650 C. for 3 hours.

Following the procedure employed in the preceding examples, 858 grams of acetone was passed over 41 grams of the phosphomolybdic acid-alumina catalyst at 350 C. and at a pressure of 70 atmospheres during a period of 20 hours. The reaction products so obtained contained 8 grams of non-condensible gas, 2'7 grams of condensible gas, and 822 grams of liquid product. The liquid product contained 475 grams of unconverted acetone, 101 grams of a mixture of water and acetic acid, grams of mesityl oxide, 22 grams of liquid material boiling between 135 and 155 C., 105 grams of a mesitylene fraction, 4 grams of liquid boiling between 170 and 206 C., 24 grams of isophorone, and 64 grams of liquid material boiling above 220 C.

Of the acetone charged, 44.7% by weight reacted. The weight yields of the different products based upon the acetone which reacted were as follows: mesitylene, 27.4%; mesityl oxide, 6.5%; isophorone, 6.3%; higher boiling liquids, 16.7%; non-condensible gas. 2.1%, and condensible gas, 7%.

The condensible gas fraction contained 9.8 mole of carbon dioxide, 8.1% propylene, 0.9% propane, 41.2% isobutylene, 2.5% n-butylene, 2.5% butane, 1% pentane, and 34.2% of unconverted acetone.

Example V Following the procedure of Example 111- and employing a fresh sample of the same catalyst,

6 densible gas, and 988 grams of liquid product. The liquid product was found to contain 757 mm; of unconverted acetone, 54 grams'oi a mixture or water and acetic acid. 5 grams of liquid boiling from 60 to C., 77 grams of a mesityl oxide fraction, 8 grams of liquid boiling from to C., 53 grams of a mesitylene fraction, 4 grams 0! liquid boiling from to 206 C., 14 grams of isophorone, and 16 grams or higher boiling liquids.

Of the acetone charged, 24% reacted. Upon the basis of the acetone which reacted. the weight per cent yields of the different products were as follows: 32.2% mesityl oxide, 22.2% mesitylene, 5.9% isophorone, 6.7% of liquids boiling above 220 C., 0.4% of non-condensible gas, and 4.6% oi condensible gas.

The character of the process of the present invention and its commercial value are evident from the preceding specificationand examples, although neither section is intended to limit the broad scopeor the invention.

We claim as our invention:

1. A process for the production or aromatics which comprises dehydrating and cyclicizing a ketone in the presence 01' a catalyst comprising a heteropolyacid at a temperature above 200 C. but not greater than about 450 C.

2. A process for the production or aromatics which comprises dehydrating and cyclicizing an alkyl ketone in the presence of a catalyst comprising a heteropolyacid at a temperature above 200 but not greater than about 450 C.

3. A process for the production of aromatics which comprises dehydrating and cyclicizing an alkyl ketone at a temperature above 200 but not greater than about 450 C. in the presence of a catalyst comprising a heteropolyacid having phosphorus as one component.

4. A process for the production of aromatics which comprises dehydrating and cyclicizing an alkyl ketone at a temperature above 200 C. but not greater than about 450 C. in the presenc of a catalyst comprising a heteropolyacid having silicon as one component.

5. A process for producing a trialkyl benzene hydrocarbon which comprises dehydrating and cyclicizing a methyl ketone at a temperature above 200 but not greater than about 450 C. in the presence of a catalyst comprising a heteropolyacid.

6. A process for producing a trialkyl benzene hydrocarbon which comprises dehydrating and cyclicizing a methyl ketone at a temperature above 200 but not greater than about 450 C. inthe presence of a catalyst comprising a heteropolyacid having phosphorus as one component.

7. A process for producing a trialkyl benzene hydrocarbon which comprises dehydrating and cyclicizing a methyl ketone at a temperature above 200' but not greater than about 450 C. in the presence of a catalyst comprising a heteropolyacid having silicon as one component.

8. A process for producing mesitylene which comprises dehydrating and cycllcizing acetone at a temperature above 200 but not greater than about 450 C. in the presence or a catalyst comprising a heteropolyacid as its essential active ingredient.

9. A process for producing mesitylene which comprises dehydrating and cyclicizing acetone at a temperature above 200 but not greater than about 450 C. in the presence of a catalyst comprising as its essential active ingredient a heteropolyacid having phosphorus as one component.

12. A process for producing mesitylene-which comprises dehydrating and cyclicizing acetone at a temperature above 200 C. but not greater than about 450 C. in the presence or a phosphomolybdic acid catalyst.

13. A process for producing mesitylene which comprises dehydrating and cyclicizing acetone at a temperature above 200 C. but not greater than about 450 C. in the presence oi a silicotungstic acid catalyst.

14. A process for the production of aromatics which comprises dehydrating and cycllcizing an alkyl ketone at a temperature above 200 C. but not greater than about 450 C. in the presence of an aqueous solution of a heteropolyacid.

15. A process for the production of aromatics which comprises dehydrating and cyclicizing an alkyl ketone at a temperature above 200 but not greater than about 450' C. in the presence or a catalyst comprising essentially a composite o! a heteropolyacid and a substantially inert carrier.

vLAmMm N. 1mm. cam. B. LINN.

REFERENCES crran The following references are of record in the file or this patent:

UNITED STATES PATENTS Number Name Date 1,977,178 Dohse Oct. 16, 1934 2,162,913 Eversole et al June 20, 1939 FOREIGN PATENTS Number Country Date 423,885 Great Britain Feb. 11, 1935 OTHER REFERENCES Ipatiefl, Berichte," 5928, pp. 2035-8.

Ellis, The Chemistry of Petroleum Derivatives" (vol. II), Reinhold Pub. Co., N. Y. city (1937). me 431. (Copy in Div. 31.)

Berkman et al., "Catalysts," Reinhold Pub. Co.,

' N. Y. city (1940). pa e 952. (Copy in Div. 3.) 

